27951: Add $ZSH_EVAL_CONTEXT and $zsh_eval_contxt

12 files changed, 188 insertions, 38 deletions

diff --git a/ChangeLog b/ChangeLog
index d34e9c20a..a1a0e6875 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2010-05-12  Peter Stephenson  <pws@csr.com>
+
+	* 27951: Doc/Zsh/expn.yo, Doc/Zsh/params.yo, Src/builtin.c,
+	Src/exec.c, Src/glob.c, Src/init.c, Src/params.c, Src/signals.c,
+	Src/Builtins/sched.c, Src/Modules/zpty.c, Src/Modules/zutil.c:
+	Add $ZSH_EVAL_CONTEXT and $zsh_eval_context to provide context
+	stack.
+
 2010-05-10  Peter Stephenson  <pws@csr.com>
 
 	* c.f. 27950: Test/C03traps.ztst some bogus whitespace got added
@@ -13122,5 +13130,5 @@
 
 *****************************************************
 * This is used by the shell to define $ZSH_PATCHLEVEL
-* $Revision: 1.4975 $
+* $Revision: 1.4976 $
 *****************************************************
diff --git a/Doc/Zsh/expn.yo b/Doc/Zsh/expn.yo
index f04d6ea17..98c8ab2df 100644
--- a/Doc/Zsh/expn.yo
+++ b/Doc/Zsh/expn.yo
@@ -2149,12 +2149,17 @@ xitem(tt(e)var(string))
 item(tt(PLUS())var(cmd))(
 The var(string) will be executed as shell code.  The filename will be
 included in the list if and only if the code returns a zero status (usually
-the status of the last command).  The first character after the `tt(e)'
+the status of the last command).
+
+In the first form, the first character after the `tt(e)'
 will be used as a separator and anything up to the next matching separator
 will be taken  as the var(string); `tt([)', `tt({)', and `tt(<)' match
 `tt(])', `tt(})', and `tt(>)', respectively, while any other character
 matches itself. Note that expansions must be quoted in the var(string)
 to prevent them from being expanded before globbing is done.
+var(string) is then executed as shell code.  The string tt(globqual)
+is appended to the array tt(zsh_eval_context) the duration of
+execution.
 
 vindex(REPLY, use of)
 vindex(reply, use of)
@@ -2288,12 +2293,13 @@ specifiers may occur to resolve ties.
 tt(oe) and tt(o+) are special cases; they are each followed by shell code,
 delimited as for the tt(e) glob qualifier and the tt(+) glob qualifier
 respectively (see above).  The code is executed for each matched file with
-the parameter tt(REPLY) set to the name of the file on entry.  The code
-should modify the parameter tt(REPLY) in some fashion.  On return, the value
-of the parameter is used instead of the file name as the string on which to
-sort.  Unlike other sort operators, tt(oe) and tt(o+) may be repeated, but
-note that the maximum number of sort operators of any kind that may appear
-in any glob expression is 12.
+the parameter tt(REPLY) set to the name of the file on entry and
+tt(globsort) appended to tt(zsh_eval_context).  The code
+should modify the parameter tt(REPLY) in some fashion.  On return, the
+value of the parameter is used instead of the file name as the string on
+which to sort.  Unlike other sort operators, tt(oe) and tt(o+) may be
+repeated, but note that the maximum number of sort operators of any kind
+that may appear in any glob expression is 12.
 )
 item(tt(O)var(c))(
 like `tt(o)', but sorts in descending order; i.e. `tt(*(^oc))' is the
diff --git a/Doc/Zsh/params.yo b/Doc/Zsh/params.yo
index 99a6e6958..55d5cda6a 100644
--- a/Doc/Zsh/params.yo
+++ b/Doc/Zsh/params.yo
@@ -722,6 +722,100 @@ vindex(VENDOR)
 item(tt(VENDOR))(
 The vendor, as determined at compile time.
 )
+vindex(zsh_eval_context)
+vindex(ZSH_EVAL_CONTEXT)
+item(tt(zsh_eval_context) <S> <Z> (tt(ZSH_EVAL_CONTEXT) <S>))(
+An array (colon-separated list) indicating the context of shell
+code that is being run.  Each time a piece of shell code that
+is stored within the shell is executed a string is temporarily appended to
+the array to indicate the type of operation that is being performed.
+Read in order the array gives an indication of the stack of
+operations being performed with the most immediate context last.
+
+The context is one of the following:
+startitem()
+item(tt(cmdarg))(
+Code specified by the tt(-c) option to the command line that invoked
+the shell.
+)
+item(tt(cmdsubst))(
+Command substitution using the tt(`)var(...)tt(`) or
+tt($+LPAR())var(...)tt(RPAR()) construct.
+)
+item(tt(equalsubst))(
+File substitution using the tt(=+LPAR())var(...)tt(RPAR()) construct.
+)
+item(tt(eval))(
+Code executed by the tt(eval) builtin.
+)
+item(tt(evalautofunc))(
+Code executed with the tt(KSH_AUTOLOAD) mechanism in order to define
+an autoloaded function.
+)
+item(tt(fc))(
+Code from the shell history executed by the tt(-e) option to the tt(fc)
+builtin.
+)
+item(tt(file))(
+Lines of code being read directly from a file, for example by
+the tt(source) builtin.
+)
+item(tt(filecode))(
+Lines of code being read from a tt(.zwc) file instead of directly
+from the source file.
+)
+item(tt(globqual))(
+Code executed by the tt(e) or tt(+) glob qualifier.
+)
+item(tt(globsort))(
+Code executed to order files by the tt(o) glob qualifier.
+)
+item(tt(insubst))(
+File substitution using the tt(<LPAR())var(...)tt(RPAR()) construct.
+)
+item(tt(loadautofunc))(
+Code read directly from a file to define an autoloaded function.
+)
+item(tt(outsubst))(
+File substitution using the tt(>LPAR())var(...)tt(RPAR()) construct.
+)
+item(tt(sched))(
+Code executed by the tt(sched) builtin.
+)
+item(tt(shfunc))(
+A shell function.
+)
+item(tt(stty))(
+Code passed to tt(stty) by the tt(STTY) environment variable.
+Normally this is passed directly to the system's tt(stty) command,
+so this value is unlikely to be seen in practice.
+)
+item(tt(style))(
+Code executed as part of a style retrieved by the tt(zstyle) builtin
+from the tt(zsh/zutil) module.
+)
+item(tt(toplevel))(
+The highest execution level of a script or interactive shell.
+)
+item(tt(trap))(
+Code executed as a trap defined by the tt(trap) builtin.  Traps
+defined as functions have the context tt(shfunc).  As traps are
+asynchronous they may have a different hierarchy from other
+code.
+)
+item(tt(zpty))(
+Code executed by the tt(zpty) builtin from the tt(zsh/zpty) module.
+)
+item(tt(zregesparse-guard))(
+Code executed as a guard by the tt(zregexparse) command from the
+tt(zsh/zutil) module.
+)
+item(tt(zregexparse-action))(
+Code executed as an action by the tt(zregexparse) command from the
+tt(zsh/zutil) module.
+)
+enditem()
+)
 vindex(ZSH_NAME)
 item(tt(ZSH_NAME))(
 Expands to the basename of the command used to invoke this instance
diff --git a/Src/Builtins/sched.c b/Src/Builtins/sched.c
index 99167e110..1ec3269bd 100644
--- a/Src/Builtins/sched.c
+++ b/Src/Builtins/sched.c
@@ -119,7 +119,7 @@ checksched(void)
 
 	if ((sch->flags & SCHEDFLAG_TRASH_ZLE) && zleactive)
 	    zleentry(ZLE_CMD_TRASH);
-	execstring(sch->cmd, 0, 0);
+	execstring(sch->cmd, 0, 0, "sched");
 	zsfree(sch->cmd);
 	zfree(sch, sizeof(struct schedcmd));
 
diff --git a/Src/Modules/zpty.c b/Src/Modules/zpty.c
index f25d442b2..2a81e68cb 100644
--- a/Src/Modules/zpty.c
+++ b/Src/Modules/zpty.c
@@ -396,7 +396,7 @@ newptycmd(char *nam, char *pname, char **args, int echo, int nblock)
 	setsparam("TTY", ztrdup(ttystrname));
 
 	opts[INTERACTIVE] = 0;
-	execode(prog, 1, 0);
+	execode(prog, 1, 0, "zpty");
 	stopmsg = 2;
 	zexit(lastval, 0);
     }
diff --git a/Src/Modules/zutil.c b/Src/Modules/zutil.c
index 698b7e3bd..76ca92f79 100644
--- a/Src/Modules/zutil.c
+++ b/Src/Modules/zutil.c
@@ -343,7 +343,7 @@ evalstyle(Stypat p)
     char **ret, *str;
 
     unsetparam("reply");
-    execode(p->eval, 1, 0);
+    execode(p->eval, 1, 0, "style");
     if (errflag) {
 	errflag = ef;
 	return NULL;
@@ -1253,7 +1253,7 @@ rmatch(RParseResult *sm, char *subj, char *var1, char *var2, int comp)
 	    char *action = getdata(ln);
 
 	    if (action)
-		execstring(action, 1, 0);
+		execstring(action, 1, 0, "zregexparse-action");
 	}
 	return 0;
     }
@@ -1278,7 +1278,8 @@ rmatch(RParseResult *sm, char *subj, char *var1, char *var2, int comp)
 		    return 3;
 	    }
 	    if (next->pattern && pattry(next->patprog, subj) &&
-		(!next->guard || (execstring(next->guard, 1, 0), !lastval))) {
+		(!next->guard || (execstring(next->guard, 1, 0,
+					     "zregesparse-guard"), !lastval))) {
 		LinkNode aln;
 		char **mend;
 		int len;
@@ -1299,7 +1300,7 @@ rmatch(RParseResult *sm, char *subj, char *var1, char *var2, int comp)
 		    char *action = getdata(aln);
 
 		    if (action)
-			execstring(action, 1, 0);
+			execstring(action, 1, 0, "zregexparse-action");
 		}
 		restorematch(&match2);
 
@@ -1328,7 +1329,7 @@ rmatch(RParseResult *sm, char *subj, char *var1, char *var2, int comp)
 		    char *action = getdata(ln);
 
 		    if (action)
-			execstring(action, 1, 0);
+			execstring(action, 1, 0, "zregexparse-action");
 		}
 		return 0;
 	    }
@@ -1339,7 +1340,7 @@ rmatch(RParseResult *sm, char *subj, char *var1, char *var2, int comp)
 	for (ln = firstnode(nexts); ln; ln = nextnode(ln)) {
 	    br = getdata(ln);
 	    if (br->state->action)
-		execstring(br->state->action, 1, 0);
+		execstring(br->state->action, 1, 0, "zregexparse-action");
 	}
     }
     return empty(nexts) ? 2 : 1;
diff --git a/Src/builtin.c b/Src/builtin.c
index d293a7a78..3f26f0304 100644
--- a/Src/builtin.c
+++ b/Src/builtin.c
@@ -1755,7 +1755,7 @@ fcedit(char *ename, char *fn)
 	return 1;
 
     s = tricat(ename, " ", fn);
-    execstring(s, 1, 0);
+    execstring(s, 1, 0, "fc");
     zsfree(s);
 
     return !lastval;
@@ -4883,7 +4883,7 @@ eval(char **argv)
 	    /* No code to execute */
 	    lastval = 0;
 	} else {
-	    execode(prog, 1, 0);
+	    execode(prog, 1, 0, "eval");
 
 	    if (errflag && !lastval)
 		lastval = errflag;
diff --git a/Src/exec.c b/Src/exec.c
index 19afc4ca4..8fd52420b 100644
--- a/Src/exec.c
+++ b/Src/exec.c
@@ -564,7 +564,7 @@ execute(LinkList args, int flags, int defpath)
 
 	STTYval = 0;	/* this prevents infinite recursion */
 	zsfree(s);
-	execstring(t, 1, 0);
+	execstring(t, 1, 0, "stty");
 	zsfree(t);
     } else if (s) {
 	STTYval = 0;
@@ -970,21 +970,40 @@ entersubsh(int flags)
 
 /**/
 mod_export void
-execstring(char *s, int dont_change_job, int exiting)
+execstring(char *s, int dont_change_job, int exiting, char *context)
 {
     Eprog prog;
 
     pushheap();
     if ((prog = parse_string(s, 0)))
-	execode(prog, dont_change_job, exiting);
+	execode(prog, dont_change_job, exiting, context);
     popheap();
 }
 
 /**/
 mod_export void
-execode(Eprog p, int dont_change_job, int exiting)
+execode(Eprog p, int dont_change_job, int exiting, char *context)
 {
     struct estate s;
+    static int zsh_eval_context_len;
+    int alen;
+
+    if (!zsh_eval_context_len) {
+	zsh_eval_context_len = 16;
+	alen = 0;
+	zsh_eval_context = (char **)zalloc(zsh_eval_context_len *
+					   sizeof(*zsh_eval_context));
+    } else {
+	alen = arrlen(zsh_eval_context);
+	if (zsh_eval_context_len == alen + 1) {
+	    zsh_eval_context_len *= 2;
+	    zsh_eval_context = zrealloc(zsh_eval_context,
+					zsh_eval_context_len *
+					sizeof(*zsh_eval_context));
+	}
+    }
+    zsh_eval_context[alen] = context;
+    zsh_eval_context[alen+1] = NULL;
 
     s.prog = p;
     s.pc = p->prog;
@@ -994,6 +1013,12 @@ execode(Eprog p, int dont_change_job, int exiting)
     execlist(&s, dont_change_job, exiting);
 
     freeeprog(p);		/* Free if now unused */
+
+    /*
+     * zsh_eval_context may have been altered by a recursive
+     * call, but that's OK since we're using the global value.
+     */
+    zsh_eval_context[alen] = NULL;
 }
 
 /* Execute a simplified command. This is used to execute things that
@@ -3571,7 +3596,7 @@ getoutput(char *cmd, int qt)
     redup(pipes[1], 1);
     entersubsh(ESUB_PGRP|ESUB_NOMONITOR);
     cmdpush(CS_CMDSUBST);
-    execode(prog, 0, 1);
+    execode(prog, 0, 1, "cmdsubst");
     cmdpop();
     close(1);
     _exit(lastval);
@@ -3725,7 +3750,7 @@ getoutputfile(char *cmd, char **eptr)
     redup(fd, 1);
     entersubsh(ESUB_PGRP|ESUB_NOMONITOR);
     cmdpush(CS_CMDSUBST);
-    execode(prog, 0, 1);
+    execode(prog, 0, 1, "equalsubst");
     cmdpop();
     close(1);
     _exit(lastval);
@@ -3827,7 +3852,7 @@ getproc(char *cmd, char **eptr)
 #endif /* PATH_DEV_FD */
 
     cmdpush(CS_CMDSUBST);
-    execode(prog, 0, 1);
+    execode(prog, 0, 1, out ? "outsubst" : "insubst");
     cmdpop();
     zclose(out);
     _exit(lastval);
@@ -3875,7 +3900,7 @@ getpipe(char *cmd, int nullexec)
     redup(pipes[out], out);
     closem(FDT_UNUSED);	/* this closes pipes[!out] as well */
     cmdpush(CS_CMDSUBST);
-    execode(prog, 0, 1);
+    execode(prog, 0, 1, out ? "outsubst" : "insubst");
     cmdpop();
     _exit(lastval);
     return 0;
@@ -4196,7 +4221,7 @@ execautofn(Estate state, UNUSED(int do_exec))
     oldscriptname = scriptname;
     oldscriptfilename = scriptfilename;
     scriptname = scriptfilename = dupstring(shf->node.nam);
-    execode(shf->funcdef, 1, 0);
+    execode(shf->funcdef, 1, 0, "loadautofunc");
     scriptname = oldscriptname;
     scriptfilename = oldscriptfilename;
 
@@ -4250,7 +4275,7 @@ loadautofn(Shfunc shf, int fksh, int autol)
 	} else {
 	    VARARR(char, n, strlen(shf->node.nam) + 1);
 	    strcpy(n, shf->node.nam);
-	    execode(prog, 1, 0);
+	    execode(prog, 1, 0, "evalautofunc");
 	    shf = (Shfunc) shfunctab->getnode(shfunctab, n);
 	    if (!shf || (shf->node.flags & PM_UNDEFINED)) {
 		/* We're not actually in the function; decrement locallevel */
@@ -4538,7 +4563,7 @@ runshfunc(Eprog prog, FuncWrap wrap, char *name)
 	wrap = wrap->next;
     }
     startparamscope();
-    execode(prog, 1, 0);
+    execode(prog, 1, 0, "shfunc");
     if (ou) {
 	setunderscore(ou);
 	zfree(ou, ouu);
diff --git a/Src/glob.c b/Src/glob.c
index 036f88ccc..c552e6cf1 100644
--- a/Src/glob.c
+++ b/Src/glob.c
@@ -1806,7 +1806,7 @@ zglob(LinkList list, LinkNode np, int nountok)
 			/* Parsed OK, execute for each name */
 			for (tmpptr = matchbuf; tmpptr < matchptr; tmpptr++) {
 			    setsparam("REPLY", ztrdup(tmpptr->name));
-			    execode(prog, 1, 0);
+			    execode(prog, 1, 0, "globsort");
 			    if (!errflag)
 				tmpptr->sortstrs[iexec] =
 				    dupstring(getsparam("REPLY"));
@@ -3497,7 +3497,7 @@ qualsheval(char *name, UNUSED(struct stat *buf), UNUSED(off_t days), char *str)
 	unsetparam("reply");
 	setsparam("REPLY", ztrdup(name));
 
-	execode(prog, 1, 0);
+	execode(prog, 1, 0, "globqual");
 
 	ret = lastval;
 	errflag = ef;
@@ -3516,6 +3516,7 @@ qualsheval(char *name, UNUSED(struct stat *buf), UNUSED(off_t days), char *str)
 		inserts = tmparr;
 	    }
 	}
+
 	return !ret;
     }
     return 0;
diff --git a/Src/init.c b/Src/init.c
index 56c8c1822..dea9aff40 100644
--- a/Src/init.c
+++ b/Src/init.c
@@ -182,7 +182,7 @@ loop(int toplevel, int justonce)
 	    }
 	    if (stopmsg)	/* unset 'you have stopped jobs' flag */
 		stopmsg--;
-	    execode(prog, 0, 0);
+	    execode(prog, 0, 0, toplevel ? "toplevel" : "file");
 	    tok = toksav;
 	    if (toplevel)
 		noexitct = 0;
@@ -1125,7 +1125,7 @@ init_misc(void)
 	    fclose(bshin);
 	SHIN = movefd(open("/dev/null", O_RDONLY | O_NOCTTY));
 	bshin = fdopen(SHIN, "r");
-	execstring(cmd, 0, 1);
+	execstring(cmd, 0, 1, "cmdarg");
 	stopmsg = 1;
 	zexit(lastval, 0);
     }
@@ -1213,7 +1213,7 @@ source(char *s)
     if (prog) {
 	pushheap();
 	errflag = 0;
-	execode(prog, 1, 0);
+	execode(prog, 1, 0, "filecode");
 	popheap();
 	if (errflag)
 	    ret = SOURCE_ERROR;
diff --git a/Src/params.c b/Src/params.c
index b19881ee7..576de2f52 100644
--- a/Src/params.c
+++ b/Src/params.c
@@ -57,7 +57,8 @@ char **pparams,		/* $argv        */
      **mailpath,	/* $mailpath    */
      **manpath,		/* $manpath     */
      **psvar,		/* $psvar       */
-     **watch;		/* $watch       */
+     **watch,		/* $watch       */
+     **zsh_eval_context; /* $zsh_eval_context */
 /**/
 mod_export
 char **path,		/* $path        */
@@ -341,6 +342,7 @@ IPDEF8("MAILPATH", &mailpath, "mailpath", 0),
 IPDEF8("WATCH", &watch, "watch", 0),
 IPDEF8("PATH", &path, "path", PM_RESTRICTED),
 IPDEF8("PSVAR", &psvar, "psvar", 0),
+IPDEF8("ZSH_EVAL_CONTEXT", &zsh_eval_context, "zsh_eval_context", PM_READONLY),
 
 /* MODULE_PATH is not imported for security reasons */
 IPDEF8("MODULE_PATH", &module_path, "module_path", PM_DONTIMPORT|PM_RESTRICTED),
@@ -349,12 +351,21 @@ IPDEF8("MODULE_PATH", &module_path, "module_path", PM_DONTIMPORT|PM_RESTRICTED),
 #define IPDEF9(A,B,C) IPDEF9F(A,B,C,0)
 IPDEF9F("*", &pparams, NULL, PM_ARRAY|PM_SPECIAL|PM_DONTIMPORT|PM_READONLY),
 IPDEF9F("@", &pparams, NULL, PM_ARRAY|PM_SPECIAL|PM_DONTIMPORT|PM_READONLY),
+
+/*
+ * This empty row indicates the end of parameters available in
+ * all emulations.
+ */
 {{NULL,NULL,0},BR(NULL),NULL_GSU,0,0,NULL,NULL,NULL,0},
 
 #define IPDEF10(A,B) {{NULL,A,PM_ARRAY|PM_SPECIAL},BR(NULL),GSU(B),10,0,NULL,NULL,NULL,0}
 
-/* The following parameters are not available in sh/ksh compatibility *
- * mode. All of these have sh compatible equivalents.                */
+/*
+ * The following parameters are not available in sh/ksh compatibility *
+ * mode.
+ */
+
+/* All of these have sh compatible equivalents.                */
 IPDEF1("ARGC", argc_gsu, PM_READONLY),
 IPDEF2("HISTCHARS", histchars_gsu, PM_DONTIMPORT),
 IPDEF4("status", &lastval),
@@ -373,9 +384,13 @@ IPDEF9("manpath", &manpath, "MANPATH"),
 IPDEF9("psvar", &psvar, "PSVAR"),
 IPDEF9("watch", &watch, "WATCH"),
 
+IPDEF9F("zsh_eval_context", &zsh_eval_context, "ZSH_EVAL_CONTEXT", PM_READONLY),
+
 IPDEF9F("module_path", &module_path, "MODULE_PATH", PM_RESTRICTED),
 IPDEF9F("path", &path, "PATH", PM_RESTRICTED),
 
+/* These are known to zsh alone. */
+
 IPDEF10("pipestatus", pipestatus_gsu),
 
 {{NULL,NULL,0},BR(NULL),NULL_GSU,0,0,NULL,NULL,NULL,0},
diff --git a/Src/signals.c b/Src/signals.c
index f67a3e8ca..74aeadde7 100644
--- a/Src/signals.c
+++ b/Src/signals.c
@@ -1198,7 +1198,7 @@ dotrapargs(int sig, int *sigtr, void *sigfn)
 	trap_state = TRAP_STATE_PRIMED;
 	trapisfunc = isfunc = 0;
 
-	execode((Eprog)sigfn, 1, 0);
+	execode((Eprog)sigfn, 1, 0, "trap");
     }
     runhookdef(AFTERTRAPHOOK, NULL);